THE HYPERHYDRICITY SYNDROME: WATERLOGGING OF PLANT TISSUES AS A MAJOR CAUSE

Hyperhydricity (also known as 'vitrification') is a physiological disorder in tissue-cultured plant material, which causes a reduction of propagation and death of tissues when transferred to ex vitro conditions. A plethora of causes has been mentioned in literature. We consider this disorder as the result of the stressful conditions brought about by waterlogging of the apoplast. This causes hypoxia and thereby leads to severe oxidative stress. We argue that hyperhydric features like vitreous appearance and wrinkled leaves are secondary events resulting from waterlogging of the apoplast. With the use of readily available technologies, the molecular components of hyperhydricity can be dissected.